<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8"/>
        <meta name="viewport" content="width=device-width, initial-scale=1.0"/>
        <meta http-equiv="X-UA-Compatible" content="ie=edge"/>
        <title>Document</title>
        <script src = 'jquery-1.10.1.min.js'></script>
        <script>
            /* 
                index() 获取当前节点在兄弟节点中的下标

                eq(下标) 通过下标获取指定的元素节点
             */
           $(function(){
            //    alert($("h3").index());
                $("li").eq(3).css("backgroundColor", 'orange');
                $("li:eq(4)").css("backgroundColor", 'yellow');
           })
        </script>
    </head>
    <body>
        <strong>storng</strong>
        <em>em</em>
        <div id = 'div1'>
                <h2>h2</h2>
                <p>p</p>
                <h3>h3</h3>
                <em>em</em>
                <div>div</div>
        </div>
        <ul>
            <li>1111</li>
            <li>1111</li>
            <li>1111</li>
            <li>1111</li>
            <li>1111</li>
        </ul>
    </body>
</html>